概華论与款程统外 0, x<0, 1/8,0≤x<1, 所以F(x)=4/8,1≤x<2, 7/8, 2≤X<3, 1, x≥3. P{1<X<3}=P{X≤3}-P{X≤1}-P{X=3} =F3)-F(1)-P{X=3} =1-413 8881 P{1  X  3} = P{X  3} − P{X  1} − P{X = 3} = F(3) − F(1) 8 1 8 4 = 1 − −                 = 1, 3. 7 8, 2 3, 4 8, 1 2, 1 8, 0 1, 0, 0, ( ) x x x x x 所以F x − P{X = 3} . 8 3 =